“I’m a fierce advocate of privacy,” Sen. Paul said on CBS’s Face the Nation Sunday. “I’ll continue to be an equal opportunity defender of the Bill of Rights, whether it’s a Republican or a Democrat president.”

Trump nominated Kansas Representative Mike Pompeo on Friday to lead the intelligence agency. Pompeo, known for his vocal criticism of the Obama administration's diplomatic deal with Iran, has also advocated expanding the surveillance powers of the National Security Agency. He’s held that position despite the moves of a Republican-controlled Congress to terminate some of the NSA’s most controversial data collection programs.

Following the Snowden revelations, Congress voted in 2015 to limit the NSA’s power to amass the phone records of millions of Americans. Since that vote, however, Rep. Pompeo has said he wants to bring those surveillance powers back. In fact, he wants to expand the government’s ability to search individuals without a warrant and amplify the surveillance of social media posts.

Referring to Rep. Pompeo’s support of the Patriot Act and the NSA’s mass collection programs, Sen. Paul said, “It does concern me.”

“[Pompeo’s] been for expanding NSA powers. Many of the NSA powers were done, I think, in secret, without the knowledge of most members of Congress. Even some members who are authors or co-authors of the Patriot Act said, ‘We never intended for them to collect all that data in Utah, and they didn’t tell us,”’ Paul said, referring to the NSA’s massive data storage facility code-named “Bumblehive.”

“So one of my questions for Pompeo will be: Are their secret programs that even Congress doesn't know about?”

Pompeo, who serves on the House Intelligence Committee, must be confirmed by majority vote in the Senate before he can take charge of the CIA.

A spokesperson for Sen. Ron Wyden, who sits on the Intelligence Committee and will evaluate Pompeo’s nomination before the vote can be opened up to the full Senate, told BuzzFeed News:

Sen. Wyden’s views on those issues are clear. He fought for years to uncover and then bring an end to dragnet surveillance of Americans’ phone records. Senator Wyden would forcefully oppose any effort to resurrect mass surveillance. The idea that the government should maintain a sprawling database of financial information, personal details and social media posts, as well as phone records is a clear violation of civil liberties, and would create an unprecedented target for foreign spies, hackers and criminals.

Sen. Mark Warner, who will become the highest ranking Democrat on the Senate Intelligence Committee congratulated Rep. Pompeo on his nomination, and appeared more supportive.

“Congressman Pompeo has a firsthand appreciation for Congress’ responsibility to provide vigilant oversight of our nation’s intelligence activities, and I look forward to learning more about his views on national security and intelligence policy and his vision for the CIA,” Warner said in statement to BuzzFeed News.

Other privacy hawks, including Rep. Justin Amash, were encouraged by Pompeo’s nomination. “He's a great pick. Yes, we have our disagreements, but Mike will listen to our concerns and serve with integrity,” he said on Twitter.

Rep. Adam Schiff, the top Democrat on the House Intelligence Committee and a leading voice behind the legislation to curb the NSA’s bulk data collection told BuzzFeed News, “Mike is very bright and hard-working and will devote himself to helping the Agency develop the best possible intelligence for policy makers.”

As complementary as Reps. Schiff and Amash were, it will be US Senators who will have final say on Pompeo.

Hamza Shaban is a technology policy reporter for BuzzFeed News and is based in Washington, DC.